Process of dyeing.



UNlTE STATES :ATE'r OFFICE.

RENE BOHN, OF MANNHEIM, GERMANY, ASSIGNOR TO BADISCIIE ANILIN AND SODA FABRIK, OF LUDWIGSHAFEN, GERMANY.

PROCESS OF DYEING.

SPECIFICATION forming part of Letters Patent No. 681,613, dated August 27, 1901. Application filed May 27, 1901. Serial No. 62,129. (No specimens.)

To all whom it may concern.-

Be it known that I, RENE BOHN, doctor of philosophy and chemist, a citizen of the Swiss Republic, residing at Mannheim, in the Grand Duchy of Baden, Germany, have invented new and useful Improvements in Processes of 1lgyeing, of which the following isa specifica- It is known that naphtha-zarin, a body which has long been used as a dyestuit, yields on reduction a compound which is considered to be tetrahydroxy-naphthalene. (See Zincke and Schn1idt,Avmctlen clcr O'lzemtc,Vol. 286, p. 37.) This body has up to the present not been used or looked upon as a dyestuff, nor has it received any industrial application. I have discovered that it is eminently suited for use as a dyestuff in that it dyes animal fiber directly and combines with metallic mordants, such as alumina or chrome, producing shades which on suitable treatment can be converted into black-lakes ofgreat intensity and fastness. The shade produced on unmordanted wool, for example, is brown, while cotton mordanted with alumina is dyed a yellowish shade, which becomes darker on exposure to air. The dyeings produced on unmordanted material become darker when treated with a suitable oxidizing agent, and if chromates, which are especially suitable, be employed a fast black-lake is formed. The dyestuff on mordanted material is converted into a black metallic lake when treated with bichromate of potash or another suitable oxidizer, which need not contain a chemically combined metal-for instance, air. The solubility of tetrahydroxy-naphthalene in water is such that the dyeings produced by its aid are of great evenness. At the same time they possess great intensity. The dyeings produced by a given weight of tetrahydroxy-naphthalene and subsequent treatment with chromates are approximately twice as intense as the dyeings produced by the same weight of alizarin-black.

In this application for Letters Patent I especially wish to claim the process for producing dyeings by means of tetrahydroxynaphthalene.

The following examples will serve to further illustrate the nature of my invention and a method of carrying the same into practical effect, but the invention is not confined to the examples. The parts are by weight.

Eat-ample 1-Dyetng woolwtth tet'rahyclrom naphthatcne.-l3oil ten (10) kilos of wool in a weak acetic-acid bath for one (1) hour with one hundred and fifty (150) to two hundred (200) grams of tetrahydroxy naphthalene. Then add one hundred and fifty (150) grams of potassium bichromate and heat for a further three-quarters of an hour.

Example 2-Dyetng silk with tetrahyclrowynaphthalene-Ten (10) kilos of silk are treated like the wool in Example 1 with the exception that three hundred (300) to four hundred (400) grams of tetrahydroxy-naphthalene are to be employed instead of one hundred and fifty (150) to two hundred (200) grams.

Example 3-Dyctng cotton with tetrahychoosy-naphthalene.-B0il ten (10) kilograms of cotton mordanted with chrome in an acetic acid bath for one (1) hour with three hundred (300) grams of tetrahydroxy-naphthalene and then add one hundred and fifty (150) grams of potassium bichromate and boil for a further three-quarters (a) of an hour.

Now what I claim is- 1. The process of dyeing which consists in treating mordanted textile fiber with tetrahydroxy-naphthalene and subjecting the fiber thus treated to the action of oxidizing agents, substantially as described.

2. The process of dyeing which consists in treating textile fiber with tetrahydroxy-naphthalene and subjecting the fiber thus treated to the action of oxidizing agents, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

RENE BOHN.

Witnesses:

JOHN L. HEINKE, PERCY J. J ONES. 

